1. Field of the Invention
This invention relates to 3-(substituted carbamoyloxy)-3-cephem derivatives, novel antibacterial compositions having excellent effects as drugs, and a process for their preparation.
2. Description of the Related Art
Japanese Patent Application Laid-Open (Kokai) No. 34794/1978 discloses unsubstituted or lower-alkyl-substituted 3-carbamoyloxy-3-cephem derivatives including the compounds represented by the following formula: ##STR3## wherein Y means a hydrogen atom or a nucleophile compound residuum.
In addition, Japanese Patent Application No. 44714/1989 discloses the compounds represented by the following formula: ##STR4## wherein R.sup.6 means an amino group or an acylamino group, R.sup.7 denotes a carboxyl group or a protected carboxyl group, the group represented by the formula ##STR5## represents a di(lower) alkylamino group, a (lower) alkylamino group, a saturated, 5- or 6-membered, heterocyclic (lower) alkylamino group containing 1-4 nitrogen atoms, said alkylamino group being optionally substituted by one or more lower alkyl groups, or a saturated, 5- or 6-membered heterocyclic group containing 2-4 nitrogen atoms, said heterocyclic group being optionally substituted by one or more lower alkyl or hydroxy(lower)alkyl groups, X.sup.1 is --S-- or ##STR6## and the dotted line indicates a 2- or 3-cephem ring,
Further, Japanese Patent Publication No., 46474/1991 discloses cephem compounds represented by the following formula: ##STR7## wherein R.sup.1 is an amino or hydroxyl group which may optionally be protected, R.sup.3 is a hydrogen atom, R.sup.5 is a hydroxyl group or a substituted or unsubstituted alkoxyl group, R.sup.8 is a hydrogen atom, Q denotes a carbon-carbon linkage for the formation of a 3-substituted-3-cephem-4-carboxylic acid, and R represents an ester residuum.
Several types of semisynthetic cephalosporins are now used for the treatment of various infectious diseases. None of them are, however, satisfactory as antibacterial agents which have strong antibacterial activities and, in particular, are orally-dosable.